1. Field of the Invention
The present invention relates to an apparatus for generating hysteresis of an electronic accelerator pedal for a vehicle.
2. Description of Related Art
In general, the accelerator pedal of vehicles is a device for adjusting the number of revolution of the engines by adjusting the intake amount of gas mixture in gasoline engines and the jet amount of fuel in diesel engines.
Most accelerator pedals widely used in recent years are mechanical accelerator pedals that adjust the amount of fuel by opening/closing the throttle valve in the carburetor, using the accelerator cable.
However, such mechanical accelerator pedals have a problem that the throttle valve and the injection pump make an error in operational range, when the tension of the accelerator cable is changed by aging or changes in the environment.
In recent years, electronic accelerator pedals that electronically control the engine and the peripheral parts have been developed to overcome the defects. In the electronic accelerator pedals, a pedal arm 2 pivots clockwise about a hinge shaft 3 when a driver presses down a pedal pad 1 shown in FIG. 1, and a sensor lever (not shown) connected with pedal arm 2 pivots by the rotation of pedal arm 2.
As the sensor lever rotates, a sensor 5 attached to a housing 4 detects an output value corresponding to the rotation of the sensor lever and transmits an electric signal to a throttle control unit, and then the throttle control unit transmits a control signal such that an actuator opens/closes the throttle valve to adjust the combustion amount.
Since such electronic accelerator pedals are not provided with an accelerator cable, the space can be saved. Further, since they are not affected by changes in tension of the cable, a driver can more smoothly operate them with reduced fatigue and it is possible to reduce fuel consumption by improving fuel efficiency.
These electronic accelerator pedals are generally equipped with an apparatus for generating hysteresis which can considerably reduce fatigue of a driver operating pedal pad 1, by making the force when the driver presses down pedal pad 1 different from the force applied from pedal pad 1 to the driver's foot when the driver releases pedal pad 1.
However, since apparatuses for generating hysteresis that have been used for electronic accelerator pedals in the related art have a large number of hinged parts, such as bolts and pivots, it is difficult to assemble them and accordingly, the assembly time significantly increases and the productivity decreases.
That is, an apparatus for generating hysteresis in the related art, as shown in FIGS. 1 and 2, includes a spring plate 7 that is rotatably linked to pedal arm 2 by a pivot 6, a friction shoe 9 of which an end is rotatably linked to pedal arm 2 by a pivot 8 and the other end is disposed to contact the inner surface of housing 4 and spring plate 7, an inner spring 10 and an outer spring 11 of which the upper ends are fixed to the upper inner surface of housing 4 and the lower ends are fixed to the spring plate 7, and a spring pad 12 a spring pad 12 that is interposed between the inner spring 10 and the outer spring 11.
As a driver presses down pedal pad 1, friction shoe 9 rotate counterclockwise about pivot 8 from the position shown in FIG. 1 and produces friction in contact with the inner surface of housing 4. Accordingly, the driver should press down pedal pad 1 against the friction force of friction shoe as well as inner spring 10 and outer spring 11.
On the contrary, when the driver releases pedal pad 1, the force applied to the driver's foot from pedal pad 1 by the friction force of friction shoe 9 becomes relatively smaller than the force when the driver presses down pedal pad 1. Therefore, hysteresis can be generated and fatigue of the driver operating pedal pad 1 is considerably reduced.
However, the apparatus for generating hysteresis in the relate art needs a several hinged parts, such as pivot 6 for linking spring plate 7 with pedal arm 2 and pivot 8 for liming friction shoe 9 with pedal arm 2, such that assembly is difficult, a large amount of time is required for the assembly, and accordingly, productivity is deteriorated.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.